Structure and energy storage performance of lanthanide elements doped AgNbO3 lead-free antiferroelectric ceramics

The aliovalent A-site modification in Silver niobate (AgNbO3, AN) antiferroelectrics has exhibited its advances in improving energy storage performance, but lack of a comprehensive understanding. In this work, 3 mol% lanthanide elements (Re: Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm) modified AgNbO3 (ReAN) ceramics were investigated. Compared with pristine AN, the ReAN ceramics exhibited decreased M1-M2 phase transition temperature and typical double-like P-E loops. The antiferroelectricity improved firstly from SmAN to TbAN because of reduction of tolerance factor, then it decayed with increasing atomic number due to partial Re3+ ions entering into B-site. Consequently, high recoverable energy density (Wrec ≈ 4.5 J/cm3) and efficiency (η ≈ 65 %) were achieved for the compositions from SmAN to TbAN under 250 kV/cm. While a general decrease in Wrec and η was observed by further increasing atomic number. This study provides a comprehensive knowledge of lanthanide element dopants in AgNbO3 system.